Gyratory grinding machine



June 7A, 1927 `1,631,247

C. N. CONRADSONy GYRATORY GRINDING MACHINE Filed June 25, 1925 2 Sheets-Sheet 1 I l; I l f i l J3 -fave/Zan 1,631,247 June 7 1927' c. N. coNRADsoN GYRATORY @HmmmI MACHINE Filed June 25. 1925 z sheets-sheet 2 Patented June 7, 1927.

i UNITEDj STATES PATENTk CFFICE.

CONRAD M. CONRADSON, OIF GREEN BAY; WISCONSIN.

vGYIAIORY GRINDING MACHINE.

Application :filed June 25, 1925. Serial No.' 39,414.

This invention relates to gyratory grinding machines and more particularly to grind- 'rfi aso-called gyratory motion.

The object of the present invention is to provide an electric driven grinding machine of the gyratory type in which the motor is incorporated in the machine, preferably with l the rotor mounted directly upon the spindle,

and the stator carried bythe rotating spindle support. y K Y l A preferred embodiment of the machine is disclosed in the accompanying drawings, in vvhich Figure 1 is a View in vside elevation of the machine with al portion thereof shown in verticalV section toy A,show the internal construction thereof; A f

Figure 2 is a view in transverse vertical section taken on line 2 2 of Figure l; and

Figure 3 'illustrates diagrammatically the arrangement of the essential parts relative to the axis ofgyration.

In Figure 1y is illustrated the head of an electric driven gyratory grinder of the, horizontal spindle type, With the driving motor contained Within the head and incorporated as integral parts of the spindle and spindle support.

The head consists primarily of a cylindric casingor housing 1, supported upon a pedestal 2, which rests upon the Hoor, said casing and pedestall being herein shown as integral with eachfother, with a Wall 3 sepa- Y rating the two and forming the bottom wall of thecasing. At each end of the casing are relatively large openings in axial alinement With each other, these openings being surrounded byV inwardly extending annular flanges 4, Within which are mounted annular bushings or collars 5 5, which support the end bearing assemblies for the rotative spindle support 6, which, as its name indicates, supports the spindle 7 through the' medium of bearings mounted in bearing retainers which are offset from the axis of the spindle support. The ends of the spindle projectingl from either end of the spindle support and Vcarrying grinding discs 8 8, preferabl consisting of circular metal plates to Whic .common to machines .of this type.

discs of abrasive material are applied to their outer faces.

Co-operating Withfeach 0f lthe grinding discs are work tables, not shown herein, but Well understood to be adjustable supports to which the Work to be operated upon is fastened, the Work tables being -moved toward and from the face of the discs in the manner Before entering upon a more detailed description of the machine and lits moving'parts, it Will be noted that the construction is the same at both ends of the machine, and parts formed at one end are duplicated at the other. A.This is particularly true of the bearing assemblies of spindle and spindle support. j' p Referring now to the construction of the spindle support 6, the 'same comprises tivo complementaryend sections 9 9, supporting between them-a central or intermediate section 10, the latter being in reality the stator of the motor and consists cfa ring having a plurality of pole pieces? l1 and coils 12 arranged about its internal circumference after the standard design of alternating current motors. The end sections 9 9 are generally conical in shape'and correspondin general to the end frame members of a motor, with their base edges bolted to the ends of the stator ring 10, and their central portions forming thebearings for the armature or rotor shaft, which in this case is the spindle 7. Thus in Figure 2 each of the end sections is a hollow casting Iwith a flaring wall portion 9a converging from the stator ring 10 to an endWise extending hub portion 9", which is journalled in the bushing 5 by means of ball bearings '13, the usual type of ball bearing retainers and other standard features of bearing design being .the spindle support is so designed that the stator rotates about an axiseccentric to its true axis, said axis, as will presently appear, being the axis of rotation of the spindle 7 Referring now to the spindle 7 and its bearings, the same extends lengthwise of the spindle support and isjournalled in bearings mounted in bearing cavities 16, vformed( within the end bearin ortions 9b these be evident from comparing thepdistance between the set of roller bearings 13, and the set of ball bearings `17, -which support the` spindle within the bearing cavity ,16. Here again the spindle bearing assembliesy are designed in accordance with the standard practice and therefore need not be described in detail, Each of the grinding discs is fixed tothe end of the spindle, preferably through the'medium of a hub 18, keyed to the tapered end of the spindle..v

Completing the spindle assembly isa rotor 23 iixedto the spindle intermediate its en'd bearings, its periphery being concentric with the axis of the spindle and also concentric with the stator .frame 10 of the spindle support. ylhe rotor is of the standard rotor design found in alternating current motors, this type of motor being preferably used, although other types may be equally Well employed.V

As will be presently disclosed, the spindle support, which includes the stator 10, rotates in its bearings, and therefore to supplycurrent to the stator coils a collector ring isused for the purpose. As apreferred design the collector ring 19 is mounted near one end of the spindle support by means of an annular flange 20, integral with'one of the end sections 9 of the spindle support, this iiange being vconcentric with the axis of rotation of the spindle support. The collector is preferably of an insulating material with a plurality of peripheral contact rings 21.

Within the casing 1 and supported on the end flange 1a thereof adjacent the collector ring is a fixed brush holder 22 comprising brushes 23 engaging the contact rings 21. rlhe brushes are connected with conductors 24 which lead to the source of current supply, Whereas the contact rings are electrically connected With coils in the usual manner, thus the' current is transmitted to the stator when in motion.

Referring now to the driving mechanism for the spindle support which, as clearly seen from the foregoing description, is in reality the stator and end frames of an alternating current motor journalled in the casing 1 of the machine, there is formed integral with the stator frame 10 and extending com pletely around the central portion thereof an integral worm wheel 25, said worm wheel being concentric with the axis of rotation of the spindle support, but eccentric to the stator frame which, as already pointed out, is concentric with the axis of the spindle 7. lnp other words, the stator androtor must necessarily be concentric with the spindle and therefore the stator is eccentric to the axis of rotation of the spindlesupport. To compensate therefore for the eccentricity of Leanser the stator the worm gear 29 is eccentric to the stator frameI in an amount exactly equal to the eccentricity between the stator frame and the spindle 7L This 'relationship between the spindle, the stator and the Worm wheel is clearly shown in the diagram of Figure 3.

Extending transversely of the casing i and beneath the stator is a shaft 26 journalled at one end in a bearing 27 supported /in one side wall of said casing. The other end of the shaft has direct driving connection with a small auxiliary motor 28, bolted to the opposite Wall of the casing. Mounted on the shaft 26 is a worm 29 which meshes with the worm wheel 25.

Thus, assuming that the current is turned v p en to both the spindle driving motor and the spindle support driving motor, the spindle is driven at a high speed and thespindle support at a relatively low speed, these two movements being imparted to the spindle simultaneously to A produce the gyratory movement of the grinding discs r8, that5 is a combined rotation ofthe discs at a high speed, and the bodily travel of the discs in a circular orbit about the axis of the spindle support. It follows therefore that during this movement there is a -relative rotation between the stator and the rotor, but, since they both rotate about a common axis, and the speed of the stator is comparatively slow,

tlie result is that the'spindle is `driven at the Y frame, a spindle support journalled in said frame for rot-ation about a. xed axis, a Spindle journalled in said support and rotative about an axis eccentric to the axis thereof, an electric motor having a stator frame forming an integral part of said spindle support and disposed ecoentrically to the axis there-- of and concentric with said spindle and a rotor mounted on said spindle, and means for driving said spindle support independ-- ently of said spindle.

2. In a grinding machine, the combination of a frame, a spindle support journalled at its ends in'said frame, a spindle .journalled eccentricallypgin said support and projecting atits ends from said housing, a grinding disc mounted at each end of said spindle,

and an electric motor comprising a statorl and rotor enclosed within said housing and mounted on said spindle support and spin? dle, respectively, and concentric Withthe axis of said spindle.

iety A 3. In a grinding machine, the combination of a housing, a spindle support journalled in said housing for rotation 'about a fixed axis, a spindle journalled in `said spindle support for rotation about an 'axis eccentric to the axis of .said support,grinding discs mounted at the ends of said spindle exterior of said housing, a motor mounted in said housing and .comprisinga stator mounted on said spindle support concentric with said spindle, and a rotorinountedon'said spindle.

4:, In a grinding 'machine the combination of a frame, a spindle support journalled in said frame for rotation about a fixed axis, a spindle journalled in said support for rotation about an axis eccentric to the axisof said support, and means for drivingfsaid spindle and spindle support comprising a motor having its stator frame forming an integral part of said support concentric with said spindle and vits rotor mounted directly on said spindle, 'and an auxiliary motor having driving connectionjwith said support.-Mn

5. A grinding machinecomprising a frame, fa spindle support journalled in Said frame, a spindle journalled eccentrically in said spindle support, ineansfory imparting rotative movement in said support, and aA vvmotor for drlving said spindle, comprising a rotor mounted on said spindle, a stator incorporated in said spindle support and ec- 4centric with. respect to'the axis of rotation thereof, a collector ring vinountedj concen- `trically on said spindle support, brushes mountedl on said frame and engaging said collector rings, 'and conductors leading to said brushes from a source of electric current and from said collector ring to said stator. y

6.v In a grinding machinethe combination of a frame housing a spindle support journailed at its ends in saidI housing, a spindle journalled eccentricall)1 in said support and extending from opposlte ends of said housing, grinding discs mounted at the ends of with-said support. i

Wist, this llthlday Signed at Green Bay, ofJune, 1925.

' CONRAD M, CONRADSONc 

